<!DOCTYPE html>
<html>
<head>
    <title>Socket.IO chat</title>
    <style>
        body { margin: 0; padding-bottom: 3rem; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; }

        #form { background: rgba(0, 0, 0, 0.15); padding: 0.25rem; position: fixed; bottom: 0; left: 0; right: 0; display: flex; height: 3rem; box-sizing: border-box; backdrop-filter: blur(10px); }
        #input { border: none; padding: 0 1rem; flex-grow: 1; border-radius: 2rem; margin: 0.25rem; }
        #input:focus { outline: none; }
        #form > button { background: #333; border: none; padding: 0 1rem; margin: 0.25rem; border-radius: 3px; outline: none; color: #fff; }

        #messages { list-style-type: none; margin: 0; padding: 0; }
        #messages > li { padding: 0.5rem 1rem; }
        #messages > li:nth-child(odd) { background: #efefef; }
    </style>
</head>
<body>
<ul id="messages"></ul>
<form id="form" action="">
    <input id="input" autocomplete="off" /><button>Send</button>
</form>
<!--<script src="/socket.io/socket.io.js"></script>-->

<script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/4.5.0/socket.io.min.js"></script>

<script>
    var socket = io();

    var messages = document.getElementById('messages');
    var form = document.getElementById('form');
    var input = document.getElementById('input');

    form.addEventListener('submit', function(e) {
        e.preventDefault();
        if (input.value) {
            socket.emit('chat-message-from-html', input.value);
            socket.emit('news', 'have news => ' +input.value);
            input.value = '';
        }
    });

    socket.on('chat-message-from-server', function(msg) {
        var item = document.createElement('li');
        item.textContent = msg;
        messages.appendChild(item);
        window.scrollTo(0, document.body.scrollHeight);
    });

    console.log("..........................");

    socket.on('connect', function () {
        console.log("连接成功");
        console.log("connect socket.connected => ", socket.connected); // true
    });

    socket.on('disconnect', function (reason) {
        console.log("disconnect reason", reason);
        console.log("disconnect");
        console.log("disconnect socket.connected => ", socket.connected); // true
    });

    socket.on("error", (error) => {
        console.log(error);
    });

    socket.on("reconnect", (attempt) => {
        console.log(attempt);
    });

    socket.on("reconnect_attempt", (attempt) => {
        console.log(attempt);
    });

    socket.on("reconnect_error", (error) => {
        console.log(error);
    });

    socket.on('message', function (msg) {
        console.log(msg);
    });

    socket.on('data', function (msg) {
        console.log(msg);
    });

    // 带有回调
    // 连接之后 会自动触发
    socket.on("hello", (arg, callback) => {
        console.log(arg); // "world"
        callback("got it 连接之后 会自动触发");
    });
</script>
</body>
</html>
